Telephone-transmitter



" no Model.)

1), DRAWBAUGH. TELEPHONE TRANSMITTER.

Patented. Abr. 17,1883.

INVENTOR. v I I {MM 0 BY MW 4 'ATTOBNEY UNITED STATES PATENT OFFICE. I

DANIEL DRAWBAUGH, OF EBERLYS MILL, PENNSYLVANIA, ASSIGNOR TO THE PEOPLES TELEPHONE COMPANY, OF NEW YORK.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 276,137, dated April 17, 1883.

Application filed December 5, 1682. (No model.)

' To all whom it may concern:

Be it known that I, DANIEL DRAWBAUGH, of Eberlys Mill, Cumberland county, Pennsylvania, have invented a new and useful Improvementin Telephone-Transmitters, of which the following is a specification.

The invention consists in the construction and arrangement of the blocks of low conducting material placed in the circuit and means of supporting the same, and alsoin the disposition of the induction-coil in a case or box attached to same back-board or base, but separated from the case or box which contains the electrodes.

In the accompanying drawings, Figure 1 is a front view of the instrument with the covers and diaphragm removed. Fig. 2 is a vertical section of the instrument on the line was of Fig. 1. Fig. 3 is arear view of the diaphragm and cover. Fig. 4 is a front view of the rear contact-piece.

Similar letters of reference indicate like parts.

A is the base or back-board of the instrument. Bis the inclosing-case for the electrodes, which case I make preferably cylindrical in form. C is the cover of said case, having a circular opening,D. The diaphragm E, of thin metal, is held, as shown in Fig. 2, between the cover 0 and the body of the case B. To the rear side of said diaphragm I attach by a rivet through its center a disk of carbon or similar low conducting material, F. In the base board A, I form a circular mortise, in the bottom of which I place a thin metal disk, G, the said disk having an arm, H, suitably bent to extend along the wall of said recess and then along the base-board A, as shown in Figs. 1 and 2. In said recess is inserted and held a cylinder, I, of wood or other non-conducting material. This cylinder is hollow, and in it I place a disk, J, of carbon or like low couductin g material, which disk J is in contact with the metal disk G. The orifice of the cylinder I comes opposite to the circular disk F on the diaphragm. Within the said cylinder I place a number of balls or polyhedrons, O, of carbon or other low conducting material, which balls are caused by gravity to lie in contact with one another and with the carbon disks F and J.

K is the induction-coil, inclosed in a separate circular case, L, having a movable cover, M. There is no opening between the interior of ease L and the interior of case B. The object of this arrangement is to allow of access to the induction coil for removal and repair without necessitating entry into the interior of case 13. Another advantage of this arrangement is that the instrument is rendered more ornamental in form. The circuits in the instrument proceed as follows: from one pole of the battery to the binding-post 1 by the wire a on the back of the case, as shown in dotted lines, to the metal contact-piece N, to the diaphragm E, and through the carbon disk F, balls 0, carbon disk J, contact-piece G, arm H, and wire b, dotted lines, Fig. 1, to the primary of theinduction-coilK, and thence by the wire I), dotted lines, to the bindingpost 2, which communicates with the other pole of the battery. The secondary circuit of the induction-coil communicates with the terminals of the main line by wires 0 0, leading to the binding-posts 3 4, with which posts are also connected wires (1 d, dotted lines, which communicate with the binding-posts 5 and 6,

to which a receiving telephone may be attached.

In operation the sounds uttered in front of So the diaphragm cause vibrations of the latter, which vibrations are in turn imparted to the low conducting plates and balls, whereby contact between the latter is modified, and the current passing through them is suitably at'- fected, to enable it to reproduce speech in a receiving-telephone. I

I am aware that a patent has hitherto been granted for a telephone containing balls of carbon arranged between two metal plates, re-

spectively connected with the diaphragm and a supporting device. This construction I do not here claim.

I claim as my invention- 1. In a telephone-transmitter, the combination of the diaphragm E, carbon disk F, balls 0, cylinder I, carbon disk J, and contact-plate G H, substantially as described.

2. In a telephone-transmitter, two boxes or cases, one inclosing the low conductors and the other an induction-coil, both boxes being secured to and upon the same side of the'baseboard of the instrument, and neither box inclosed within the other, substantially as described.

M. W. JACOBS. 

